Contact structure having a compliant bump and a testing area and manufacturing method for the same

ABSTRACT

A contact structure having both a compliant bump and a testing area and a manufacturing method for the same is introduced. The compliant bump is formed on a conductive contact of the silicon wafer or a printed circuit board. The core of the bump is made of polymeric material, and coated with a conductive material. In particular, the compliant bump is disposed on the one side of the conductive contact structure that includes both the bump and the testing area, wherein the testing area allows the area to be functionality tested, so as to prevent damage of the coated conductive material over the compliant bump during a probe testing.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a divisional of copending application Ser. No.11/603,909, filed Nov. 24, 2006, and the right of priority of parentapplication is and was claimed under 35 USC §119 of TaiwaneseApplication No. 095127901, filed Jul. 28, 2006, the entire disclosure ofwhich is incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a contact structure having a compliantbump and a testing area and a manufacturing method for the same, andmore particularly to a shift conductive compliant bump formed as aninput/output contact on a silicon wafer.

2. Description of Related Art

To develop the field of manufacturing a high-density integrated circuit,an IC chip requires a highly-reliable physical and electrical structure.In order to manufacture a high-density IC structure, such as ahigh-resolution liquid crystal panel, in a tiny area, the control ICsused therein also need to be arranged densely. As such, conventionalmetal bumps formed as the conductive contacts used on the wafer weredeveloped. The bump is either a gold bump, an eutectic solder bump, or ahigh lead solder bump, etc. Because the metal bumps used as the ICsignal contacts are used upon smaller packaged products having aplurality of pins, the conventional technology of bonding or leading isnot adopted.

U.S. Pat. No. 4,749,120 discloses a gold bump used as the conductivemedium between the IC chip and the substrate. However, the process isthe same as an assembling process combining the IC chip and thesubstrate and causes the chip to crack since a recovering force isgenerated in the duration of the process. Therefore, the prior artincorporates a conductive particle with elasticity or a relevantmaterial of the like for preventing the above-mentioned crack.

U.S. Pat. No. 5,707,902 shown in FIG. 1 discloses a cross-sectional viewof a bump structure formed on a circuit board. The major structure has ametal pad 16 formed on a substrate 1, and a passivation layer 18 havinga protective function. The bump structure on the substrate 1 includes apolymer 12 and a conductive metal layer 14 coated thereon. Inparticular, the polymer 12 reduces the recovering force between thesubstrate and the circuit board.

A bump electrode for connecting electronic components disclosed in U.S.Pat. No. 5,477,087 is shown in FIG. 2. The cross-sectional view of thebump electrode on the circuit board shows a bump electrode 20 formed ona LSI chip 21, and an aluminum electrode 22 on the LSI chip 21. Theelectrode can be the conductive medium between the bumps and thecircuit, and coated with insulation 23, furthermore, a barrier-metallayer 24 is formed between the etched insulations 23. The bump electrode20 includes a resin 25, numerous cavities 26 thereon, and a conductivemetal layer 27 coated thereon. The above-mentioned resin 25 in the bumpelectrode 20 and the cavities 26 are a compliant structure, whichprevents damage occurring in the process of combining the chip with thebump electrode 20 or a circuit board and other components.

A further prior art is U.S. Pat. No. 5,508,228 which discloses thecompliant electrically connective bumps for an adhesive flip chipintegrated circuit device. FIG. 3 shows a three-dimensional view of theconductive bump, which is a portion of the IC 30. The plurality ofconductive bumps 31 thereon is formed as the I/O contacts, and theconductive bumps 31 are prominent bumps. In particular, the top surface34 and the adjacent side structure 36 connect to the bond pads 33coupling to the IC 30 via the base 38, and the conductive bumps 31connect to the wires 32 of the IC 30 via the bond pad 33. Polymer isused to manufacture the core of the above conductive bumps 31, so thebumps have compliant features.

The bump structures disclosed in the above-mentioned art are required topass a variety of electrical examinations before being sold. The metallayer coated on the compliant bump structure can be broken when beingprobed by a probe since the metal layer is very thin. TW Patent No.324847 discloses a complex bump structure used for an IC. FIG. 4 showsthe input/output contacts of the IC, wherein the complex-type bumpstructure is formed on a substrate 40 having an input/output terminalpad 42 and a passivation layer 41 coated thereon. A first metal layer 43is formed on the input/output terminal pad 42 and the passivation layer41. Next, the patterned complex bump 44 is formed on the first metallayer 43 and on the input/output terminal pad 42 moved a shift distanceaway. After that, the first metal layer 43 and the complex bump 44 areformed as a second metal layer 45. The mentioned complex bump 44 formsan opening so as to electrically connect to the lower structure andother electric components, and the opening can be an area used forproviding a good probing place.

SUMMARY OF THE DISCLOSURE

In the conventional art, the polymeric material coated with a conductivelayer forms a conductive bump, which prevents damage suffered on theelectrical components when the conductive bump is pressed on to asubstrate. However, the surface of the conductive layer can still bedamaged when being probed by a probe. Even though the conventional artsdisclose the bump structure used for probing by the probe, the presentinvention provides a different contact structure merely having aconductive metal layer coated on the bump structure. Furthermore, theconductive metal pad of the present invention is provided to jointlyhave both the bump structure and a testing area.

The present invention relates to a contact structure having a compliantbump and a testing area and the manufacturing method of the same. Thecompliant bump forms the conductive contact of a silicon wafer or acircuit board. The core of the compliant bump is formed by a polymericmaterial and coated by a conductive material. One of the preferredembodiments of the present invention has the bump structure disposed ona side, therefore, the contact structure can include both the bumpstructure and the testing area.

A silicon wafer is used as the metal pad of an input/output contact inthe preferred embodiment of the present invention, and the metal pad ofthe contact is formed having both the compliant bump and the testingarea. In particular, the surface metal of the compliant bump provideselectrical connectivity, and the testing area provides the area toperform the electrical probe.

In the preferred embodiment of the present invention, the manufacturingmethod has a first step of preparing a substrate, wherein the contactstructure is included at least. Afterward, the polymeric material iscoated on the contact structure, and the polymeric material is etched inthe steps of developing/etching. Next, the portion which has notundergone the steps of developing/etching forms the compliant bump, andthe portion undergoing the steps forms the testing area. After that, theconductive material is coated thereon, and the compliant bump forms aconductive bump so as to electrically connect with the testing area bymeans of the conductive material. Therefore, the conductive materialcoated on the bump won't be damaged by probing the electricalcharacteristics of the contact structure.

Another embodiment of the present invention shows the steps of themethod for manufacturing the contact structure. A silicon wafer isprepared in the first step, and the wafer has a metal pad that is aninput/output terminal, and a passivation layer that is a body used toprotect the wafer. Next, a polymeric material is coated upon the siliconwafer. The polymeric material is developed and etched afterward, and theportion that has not undergone the steps of developing/etching forms acompliant bump, and the rest portion of the material forms a testingarea. Next, a micro-bump structure is disposed on the compliant bump,and a conductive metal layer is coated on the cmmpliant bump and thetesting area. The compliant bump forms a conductive bump, and theconductive bump and the testing area electrically connect with theconductive metal layer. Thereby the conductive bump and the testing areaare turned on. The electrical characteristics of the contact structureare obtained by means of the testing area, and the conductive metallayer coated on the bump is not damaged.

BRIEF DESCRIPTION OF DRAWINGS

The present invention will be readily understood by the followingdetailed description in conjunction with accompanying drawings, inwhich:

FIG. 1 is a schematic diagram of the cross-sectional view of a bumpstructure on a PCB of the prior art;

FIG. 2 shows a cross-sectional diagram of the conductive electrode ofthe prior art;

FIG. 3 shows a perspective diagram of a conductive bump formed on anintegrated circuit chip of the prior art;

FIG. 4 is a schematic diagram of the bump structure of the prior art;

FIG. 5 is a schematic diagram of the contact structure applied to aglass substrate and a chip of the present invention;

FIG. 6 shows a schematic diagram of the contact structure having acompliant bump and a testing area of the present invention;

FIGS. 7A through 7I show a cross-sectional diagram of the contactstructure of the present invention;

FIGS. 8A and 8B show the embodiment of a probe contacting the testingarea of the contact structure;

FIGS. 9A through 9C are perspective diagrams of the contact structure ofthe present invention;

FIGS. 10A through 10F are schematic diagrams of the contact structure ofthe preferred embodiment of the present invention;

FIGS. 11A through 11D show the contact structure of the embodiment ofthe present invention;

FIG. 12 is a schematic diagram of the contact structure of the presentinvention;

FIG. 13A and FIG. 13B show the contact structure disposed on a substrateof the preferred embodiment of the present invention;

FIG. 14 is a schematic diagram of the contact structure arranged on thesubstrate of the present invention;

FIG. 15 is a flow chart of the manufacturing method of the presentinvention;

FIG. 16 is a flow chart of the manufacturing method of anotherembodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

To understand the technology, means and functions adopted in the presentinvention further, reference is made to the following detaileddescription and attached drawings. The invention shall be readilyunderstood deeply and concretely from the purpose, characteristics andspecifications. Nevertheless, the present invention is not limited tothe attached drawings and embodiments in the following description.

There are two shortcomings in the conventional art that the presentinvention aims to overcome. Firstly, the cracks that occur at a contactstructure during the process of pressing by a recovering force, andsecondly the problem of it being difficult to perform a test since thereis no specific testing area or any conductive bump on the contactstructure to be tested. For overcoming the shortcomings, the presentinvention provides a contact structure having a compliant bump and atesting area, and a manufacturing method for the same. The compliantbump forms the conductive contacts, such as the input/output terminals,disposed on an IC chip or a PCB. Furthermore, the core of the bump ismade of a polymeric material or polymer, and the bump is coated with aconductive material. The structure of the preferred embodiment of thepresent invention prevents the above-mentioned cracks from appearing inthe manufacturing process.

The preferred embodiment uses only one conductive metal layer, and thecompliant bump disposed on part of the contact structure forms theconductive bump moved a shift distance away. Moreover, the contactstructure has the bump and the testing area simultaneously, wherein thetesting area is used for external testing to prevent the coated metallayer from being damaged by direct probing of the polymeric compliantbump.

Flip-chip technology of the prior art is applied to a manufacturineprocess of a liquid crystal display, wherein a substrate that is mostlymade of glass, and bare chip technology is used to connect the othercomponents with the glass substrate directly, namely a chip on glass(COG). In particular, a bare chip technology can reduce the signalingdistance between the chip and the substrate, which is compatible withpackaging for high-speed devices. After that, the size of the IC can bescaled down, the packaging density can be raised, and the weight can bereduced, so the display panel can be lighter and reach thehigh-resolution requirements of the panel.

Reference is made to FIG. 5, which shows a portion of the glasssubstrate 50 of a liquid crystal display. A plurality of driver ICs 54,54′ or other chips for signaling is disposed on the two sides of thesubstrate using the above-mentioned method of flip-chip technology toelectrically connect to PCBs 52, 52′. The contact structure having thecompliant bump and the testing area of the present invention can be usedfor the chips bridging the PCBs 52, 52′ and the glass substrate 50 toelectrically connect with each other.

One of the preferred embodiments of the present invention is shown asFIG. 6. A metal pad 60 having both the polymeric compliant bump 61 andthe testing area 65 are illustrated. The metal pad 60 is disposed on acontact above the substrate 6, such as the input/output contacts of anintegrated circuit chip, or the conductive contacts between a circuitboard and other electronic components. The structure shown in FIG. 6includes one or a plurality of metal pads 60 disposed on the substrate6. In an exemplary embodiment, the substrate 6 is provided whichelectrically couples to other electronic components. The preferredembodiment of the substrate 6 forms the integrated circuit chip, whereina passivation layer 67 is coated above and disposed on the ambient areaof the metal pad 60. Therefore, the metal pad 60 is exposed to theuncovered passivation layer 67.

In this present embodiment, the polymeric compliant bump 61 forms apyramid-shaped bump. The top surface of the compliant bump 61 andanother part thereon are coated with the conductive material 63 so as toelectrically contact the metal pad 60 and other components contactingthe bump. The polymeric compliant bump 61 is disposed on the partialsurface of the above-mentioned metal pad 60, wherein the area notcovered by the polymeric compliant bump 61 forms a testing area 65,which is provided to be probed by contacting the area. The conductivematerial 63 coated on the polymeric compliant bump 61 is also coated onthe testing area 65 of the metal pad 60, whereby the bump 61 and themetal pad 60 are contacted. The mentioned polymeric compliant bump 61with the conductive material 63 coated thereon forms a conductivecompliant bump, such as the adjacent structures lined up in a row as canbe seen in the figure. The bump can be disposed on any position upon themetal pad 60, or can span the area of the metal pad 60.

Reference is made to FIG. 7A, which shows a profile of the embodimentshown in FIG. 6. The metal pad has both the polymeric complaint bump andthe testing area. In this embodiment, the under structure is anintegrated circuit chip 70, and the surface thereon includes a metal pad75, which is used to electrically connect the chip and other electroniccomponents. Moreover, a passivation layer 74 is disposed on the ambientarea of the metal pad 75 and used to protect the integrated circuit chip70. In particular, the metal pad 75 is developed outside the passivationlayer 74.

Next, a polymeric compliant bump 73 is disposed on a partial area of thesurface of the mentioned metal pad 75. Referring to an exemplaryembodiment shown in FIG. 7A, the compliant bump 73 is disposed at theend of the metal pad 75. The area of the metal pad 75 that has not beencoated by the polymeric complaint bump 73 forms a testing area 712,which is provided to be contacted by a probe. A conductive layer 71 isformed on the top surface 731 of the polymeric compliant bump 73, andthe conductive layer 71 extends from the compliant bump 73 to the topsurface of the metal pad 75 by passing through the side part 732 of thecompliant bump 73. Therefore, the polymeric compliant bump 73 connectsto the mentioned metal pad 75 via the conductive layer 71.

FIG. 7B shows a schematic diagram of another embodiment of the mentionedcontact structure. FIG. 7B shows that the polymeric compliant bump 73can be disposed on any area of the metal pad 75, or a partial areathereon can be coated with the passivation layer 74. Namely, part of thematerial of the polymeric compliant bump 73 is coated upon thepassivation layer 74.

The aforementioned FIG. 7A shows the edge of the polymeric compliantbump 73 covering one end of the passivation layer 74. FIG. 7B shows theedge of the polymeric compliant bump 73 maintaining a distance from thepassivation layer 74. FIG. 7C, in particular, shows the edge of thepolymeric compliant bump 73 covering a greater amount of the passivationlayer 74 than in FIG. 7A.

Next, reference is made to FIG. 7D showing the edge of the polymericcompliant bump 73 covering the top side of the passivation layer 74.Additionally, the partial side part 701 or the partial top surface ofthe polymeric compliant bump 73 doesn't include the conductive layer 71since the conductive layer 71 coated on the bump 73 merely needs theconductive layer 71 on the side part 732 to conduct the metal pad 75. Inother words, the conductive layer 71 on the top surface 731 of thepolymeric compliant bump 73 conduct the testing area 712 passes throughthe conductive layer 71 on the side part 732. Therefore, the ambientsurface of the polymeric compliant bump 73 can be fully or partiallycoated by the conductive layer 71, and both of the above embodiments canachieve electrical conduction.

FIG. 7E shows a derivational embodiment from the embodiment shown inFIG. 7D. On one side of the metal pad 75, an external compliant bump 77is disposed on the outside of the polymeric compliant bump 73corresponding to the contact structure. The edge of the polymericcompliant bump 73 covers one end of the passivation layer 74. Theconductive layer 71 not only covers the top surface of the polymericcompliant bump 73, but also covers the external compliant bump 77. Thisexternal compliant bump 77 is used to enhance the total contact area andthe number of contact bumps, so as to reduce the contact structure'sresistance and prevent cracks from appearing.

Similar to FIG. 7E, FIG. 7F also shows an external compliant bump 77disposed on an outside of the polymeric compliant bump 73 correspondingto the contact structure. In particular, this external compliant bump 77is a dummy bump. The conductive layer 71 is not coated on this externalcompliant bump 77, so is dummy bump is used as a stopper for electricalsignals, and to protect the polymeric complaint bump 73 from cracking.

The embodiment shown in FIG. 7G refers to the embodiment shown in FIG.7D. The edge of the polymeric compliant bump 73 covers the top side ofthe passivation layer 74. The partial side part 701 and partial topsurface of the polymeric compliant bump 73 are not coated with theconductive layer 71. In particular, the external compliant bump 77 isalso disposed on outside of the contact structure. This externalcompliant bump 77 is also a dummy bump acting as a stopper of electricalsignals, and for protecting the bump 73 from cracking.

FIG. 7H shows an embodiment similar to FIG. 7D, where the edge of thepolymeric compliant bump 73 covers the top side of the passivation layer74, and the top surface of the polymeric compliant bump 73 is coatedwith the conductive layer 71. The external compliant bump 77 is alsodisposed on an outside of the contact structure. This external compliantbump 77 is also a dummy bump acting as a stopper of electrical signals,and for protecting the bump 73 from cracking.

The embodiment shown in FIG. 7I is similar to the embodiment shown inFIG. 7H. The edge of the polymeric compliant bump 73 covers thepassivation layer 74. However, not mnly the top surface of the polymericcompliant bump 73 but also the surfaces (top and side) of the externalcompliant bump are coated with the conductive layer 71. This externalcompliant bump 77 is used to enhance signal transmission and the contactbetween the electronic components. Protection of the polymeric compliantbump 73 from cracking is also provided.

FIG. 8A shows a probe 80 contacting the testing area 712 of the contactstructure of the present invention. The contact structure having thecompliant bump and the testing area is used to improve the contactstructure of the prior art, which doesn't provide any specific area forprobing. Furthermore, the conductive layer coated on the polymericcompliant bump 73 is very thin (for example, less than micro-meter), sothe area to be contacted by probing can be easily damaged. Theconductive layer 71 on the testing area 712 shown in the figure conductsthe silicon wafer or circuit board beneath the contact structure via themetal pad 75, which is provided for easy testing and preventing theconductive layer 71 from being damaged.

FIG. 8B shows a schematic diagram of the polymeric compliant bumps 82,83 which are disposed on two ends of the metal pad 75. The metal pad 75and the polymeric compliant bumps 82, 83 are coated with the conductivematerial to form a conductive layer 81. The present structure improvesthe conductive structure of the prior art.

The probe 80 directly contacts the testing area 812 between the twocompliant bumps 82, 83 for testing the electrical characteristics of theentire device. The testing area 812 conducts below the substrate, suchas the silicon wafer 70, via the metal pad 75 for facilitating easytesting. Thereby, the conductive layer 81 coated on the compliant bumps82, 83 won't be damaged.

Other embodiments are shown in FIG. 9A to FIG. 9C. The mentionedsubstrate 9 can be a silicon wafer or a circuit board, wherein the metalpad 90 having both the testing area 95 and the conductive bumps (91,91′, 91″) connects to the input/mutput terminals of the externalelectronic components. In the preferred embodiment, the cores of theconductive bumps (91, 91′, 91″) are made of polymeric material, and thecontact structure is coated with a conductive layer. The conductivelayer coated on the surface of the structure extends to the surface ofthe testing area 95. Therefore, the testing area 95 is probed instead ofthe conductive bumps (91, 91′, 91″) being electrically tested (as in theprior art). Such a method is more convenient and moreover protects thebumps (91,91′,91″) from being damaged in the testing process.

FIG. 9A shows that the conductive bumps 91 are designed as cone-shapedbumps. In particular, there is a plurality of cone-shaped bumps so as toenhance the reliability of electrical contact.

FIG. 9B shows that the conductive bumps 91′ form an array having aplurality of compliant bumps so as to enhance the reliability ofelectrical contact.

The bigger conductive bumps 91″ shown in FIG. 9C provide a larger toparea. Referring to the figure, the bottom of the conductive bump 91″crosses the metal pad 90 and covers the substrate 9. This kind ofstructure enhances the reliability of electrical contact.

Next, FIGS. 10A to 10F show the embodiments of the contact structure ofthe present invention. As shown in the figures, a substrate 10 can be asilicon wafer or a circuit board. A metal pad 100 is used to connect theinput/output terminals of the external electronic components. Similarly,the contact structure has both the testing area and the conductive bumps101 a, 101 b, 101 c, 101 d, 101 e, 101 f.

In FIG. 10A, the conductive bump 101 a is formed as a cross-shaped bump.By means of a variety of bumps, the conductivity between the contactstructure and the mounted electronic components is improved,specifically the structure in a display panel. In particular, theposition of the conductive bump 101 a is not limited to one end of themetal pad 100 as shown in the figure. The bump can be disposed on anyposition on the metal pad 100, or even crossing the metal pad 100 andcontacting the substrate 10.

Reference is made to FIG. 10B. The conductive bump 101 b of the presentinvention can have a double-cross-shaped. The position of the conductivebump is not limited to one end of the metal pad 100 as shown in thefigure. The bump can be disposed on any position on the metal pad 100,or even crossing the metal pad 100 and contacting the substrate 10.

FIG. 10C shows that the conductive bump 101 c can be a U-shaped bump.The bump is disposed on the metal pad 100, and is not limited to bedisposed on any position shown in the figure. The bump can cross themetal pad 100 and contact the substrate 10.

FIG. 10D shows the conductive bump 101 d as a bar-shaped bump FIG. 10Eshows the conductive bumps 101 e can be formed as a plurality ofparallel and bar-shaped polymeric compliant bumps. The bumps can bedisposed upon any position on the metal pad 100, or even crossing themetal pad 100 and contacting the substrate 10.

The conductive bump 101 f shown in FIG. 10F is made of a plurality ofaligned bar-shaped (or two-bar-shaped or three-bar-shaped) compliantbumps. Moreover, the bottom structure of the aligned conductive bumps101 f crosses the two sides of metal pad 100, and covers the substrate10, so as to enhance the reliability of electrical contact in use.

The embodiments of the above-mentioned conductive bumps are implementedas line-shaped bumps mostly, and the bumps are disposed in the metalpad. Moreover, only one conductive layer is coated on the bumps and thetesting area to achieve the electrical probing and conductivity jointly.The line-shaped conductive bumps can increase the contact area used forconducting the bumps and other electronic components.

Another embodiment of the contact structure of the present invention isshown in FIG. 11A. A substrate 110 such as a silicon wafer forms a base,and a metal pad 113 is formed thereon. A passivation layer 111 isdisposed on the ambient area surrounding the metal pad 113 forprotecting the substrate 110. Moreoter, the metal pad 113 is exposed,and a polymeric compliant bump 112 is formed on a side of the metal pad113. Furthermore, the bump 112 doesn't cover the whole area of the metalpad 113, whereas a conductive layer 114 is coated on the metal pad 113and the polymeric compliant bump 112, so a testing area on the metal pad113 is formed on the area not covered by the bump 112.

In this figure, the top surface of the polymeric compliant bump 112 ismade of a plurality of micro bumps 115. The micro bumps 115 can be madeof a multi-bump structure formed directly on the polymeric compliantbump 112, and formed as a tough surface after being coated with theconductive layer. Furthermore, the micro bumps 115 can also be made ofat least one separate micro compliant bump, and coated with theconductive layer. By means of the mentioned micro bumps, the contactstructure can achieve the electrical contact with smaller stress duringassembly. The plurality of micro bumps can form a single line, multiplelines or an array type.

FIG. 11B shows a perspective view of the contact structure in accordancewith a preferred embodiment of FIG. 11A. The above structure of thesubstrate 110 is clearly shown in this diagram, which has thepassivation layer 111 and the metal pad 113 covering the substrate 110.The metal pad 113 essentially includes a conductive bump 118 and atesting area 117. The conductive bump 118 is composed of the polymericcompliant bump 112 and the conductive layer 114 coated on the surface.In this preferred embodiment, the conductive bump 118 further includesthe micro bumps 115 made of a plurality of particles. A partialstructure of the polymeric compliant bump 112 of the other embodimentcrosses the passivation layer 111.

Next, FIG. 11C shows another embodiment of the contact structure. Thesubstrate 110 (such as the silicon wafer) also forms a base. The metalpad 113 is formed thereon, and the passivation layer 111 is formed onthe ambient area of the metal pad 113. Moreover, a partial area of themetal pad 113 is exposed to an outside of the surface. The polymericcompliant bump 112 is formed at one end of the contact structure, andjust a partial area thereof covers the metal pad 113. A feature of thisembodiment is that the top surface of the polymeric compliant bump 112has a micro concave structure 116 having a plurality of micro holes. Themicro concave structure 116 disposed on the conductive layer 114 forms arough surface on the contact structure. Therefore, by means of theabove-mentioned micro concave structure, the contact structure can haveelectrical contact with less stress during an assembly process withother electronic components. Wherein, the plurality of micro concavestructure can form a single line, multiple lines, or an array type.

FIG. 11D shows a perspective diagram of the contact structure, whereinthe metal pad 113 and the polymeric compliant bump 112 are coated withthe conductive layer 114, and form the testing area and conductive(conductive bump 119) area respectively. Above the substrate 110, thepassivation layer 111 and the metal pad 113 are formed thereon. Both thetesting area 117 and the conductive bump 119 having the plurality ofmicro concave structures 116 are formed above the metal pad 113. In thisembodiment, the conductive bump 119 is the structure formed within themetal pad 113. Furthermore, the conductive Reference is made to FIG. 12,which shows a contact structure of the present invention having one ormore bar-shaped conductive bumps combining the bumps on the adjacentcontact structures in a row. For example, these bar-shaped conductivebumps can be applied for the chip-on-glass (COG), wherein eachintegrated circuit chip is arranged to electrically couple with a glasssubstrate and the external circuit. In this figure, since the conductivebumps of the contacts on the substrate 120, such as the mentioned ICchip, are disposed regularly, the adjacent polymeric compliant bumps 122can be manufactured as bar-shaped bumps. After that, the bar-shapedbumps are coated with a conductive layer to form bar-shaped conductivebumps

FIG. 13A shows a perspective diagram of the embodiment of the presentinvention. A plurality of contact structures is disposed regularly on asubstrate 130, such as the IC chip of the embodiment. Each contactstructure has both a conductive bump 131 and a testing area 133 disposedon the metal pad. The conductive bump 131 is a compliant bump coatedwith the metal conductive layer, and the metal conductive layer iscoated on the partial surface or entire surface area of the compliantbump.

FIG. 13B shows the conductive bumps 131 formed on the adjacent contactstructures are disposed irregularly. In this embodiment, the adjacentconductive bumps 131 and the testing areas 133 are formed on the ends ofthe metal pads, but not arranged in a row. Furthermore, anotherembodiment shows the adjacent conductive bumps 131 and the testing area133 are disposed on any position of the metal pad.

FIG. 14 shows a plurality of contact structures disposed on a substrate140, and the conductive bumps 141,142,143 are arranged irregularly. Theconductive bumps can be disposed on any part of the metal pads 145, evenany position except for outside of the pads 145. Furthermore, eachconductive bump includes only one conductive layer, and this conductivelayer is coated on the position occupied by the compliant bump andposition of the metal pad 145 unoccupied by the bump. Therefore, theposition unoccupied by the compliant bump can be used for probing,wherein the conductive layer directly conducts the metal pad 145 below,and conducts the substrate 140, so as to form a convenient testing area.

The conductive bump disclosed in aforementioned embodiments is thestructure occupying part of the metal pad. The preferred embodimentshows the metal pad's area occupied by the bump being under 90 percent.

The contact structure disclosed in the present invention can be used forassembling a flip chip. For example, the driving IA chips and theelectronic components used for the liquid crystal display are disposedon a thin-film directly for achieving a slim and small device, namelythe Chip on Film (COF) technology. The contact structure of anotherembodiment is used for assembling a flip chip on a glass substrate(COG), namely the chip being flipped and assembled on the glasssubstrate. In particular, the mentioned substrate can be an organic orinorganic material such as ceramic, metal, glass, or polymeric material.

The conductive bump forms a compliant bump having a core made of apolymeric material, which can be polymide (PI), epoxy, or acrylic . . .etc. After patterning the polymeric material layer, the compliantstructure is formed on a partial area of the metal pad. Since thecompliant structure is provided, the reliability of compliant contact isformed during the assembly process of the electronic components. Thearea not covered by the conductive bump is provided for testing by aprobe.

FIG. 15 shows a flow chart of the major steps of the method formanufacturing the contact structure. The preferred embodiment of thecontact structure having both the compliant bump and the testing area isapplied for the metal pad having an input contact, an output contact,and a passivation layer.

To begin the manufacturing steps, a substrate is prepared, and thesubstrate has at least one metal pad which is a contact structure (whichcan be an aluminum electrode). The electrodes are the input/outputcontacts used as an electrical contact of the device (step S151). Afterthat, a polymeric material is coated upon the substrate, namely on thecontact structure (step S153). Next, the polymeric material is patternedby means of developing/etching, such as a dry etching means or a wetetching means, in accordance with the requirements of the contactstructure (step S155). In the other embodiment of step S155: thepolymeric material is a kind of photosensitive material, so it can beetched by a light source. Namely, a photosensitive area of the polymericmaterial is exposed under an optical mask by ultraviolet radiation.After eliminating the mask, the occupied area for a bump is formed onthe partial area occupied by the metal pad.

Next, the patterned polymeric material forms a compliant bump on themetal pad. After that, a conductive layer is coated thereon, so as toform the conductive layer. For example, a metal material is formed bythe process of sputtering or photo-etching on the compliant bump and thearea to be tested. Afterward, the compliant bump forms a conductive bump(step S157). Therefore, the metal pad is separated into a conductivebump area and a testing area (step S159).

The conductive bump and the testing area are electrically coupled bymeans of the conductive layer. The test for the device uses a probe tocontact the testing area directly, so the electric characteristics ofthe contact structure having the conductive bump can be tested preciselywithout damaging the metal layer on the conductive bump.

The contact structure of the present invention is applied to theintegrated circuit chip. FIG. 16 shows a flow chart of the manufacturingmethod.

A silicon wafer is prepared, and the wafer includes a metal pad formedas an input/output terminal, and a passivation layer which is used toprotect the body of the wafer (step S161).

Next, the silicon wafer is coated with the conductive layer (step S163).After that, by means of developing/etching, the polymeric material ispatterned under the optical mask, and the useless part is eliminated, soas to form one or a plurality of compliant bumps and the testing area onthe metal pad (step S165).

In this embodiment, a plurality of micro bumps is manufactured upon thementioned compliant bump, then the contact structure can achieve theelectrical contact with smaller stress during an assembly process forthe IC chips and other electronic components (step S167).

For example, the mentioned polymeric compliant bump is directly formedas a bump with a plurality of convex structures, so as to form a touehsurface. In another embodiment, a plurality of independent micro concavebumps is formed on the compliant bump. In particular, the micro bumpscan be formed as a single line, multiple lines, an array, or aninterlaced type.

After that, the structure is coated with a conductive layer, which canbe formed by means of sputtering and photo-etching (step S169). In themeantime, a conductive bump is formed on the partial area of metal padoccupied by the bump, and a testing area is formed on the areaunoccupied by the bump (step S171).

The above-mentioned embodiments disclose the main features of thepresent invention, including:

-   -   (1) the conductive compliant bump can be disposed on any        position of the metal pad in accordance with actual        requirements;    -   (2) the conductive compliant bump occupies the partial area of        the metal pad;    -   (3) the metal pad is separated into a bump area and a probe        testing area;    -   (4) the conductive compliant bump is formed within the metal pad        or partially crossing the metal pad;    -   (5) the conductive material covers a partial or an entire        surface area of the conductive compliant bump;    -   (6) the conductive compliant bump can be rectangular, circular,        or triangular in shape, or any combination thereof;    -   (7) the conductive compliant bump can have a rough surface; and    -   (8) the area of the metal pad occupied by the conductive        compliant bump is less than 90 percent.

In summary, the present invention relates to a contact structure havingboth a compliant bump and a testing area, and a manufacturing methodthereof. The present invention allows the reduction in size of bumps andthe recovering force when assembling the structure. Furthermore, thetesting area is used in order that the device may be testedconveniently, and costs are reduced due to only one metal layer beingused.

The many features and advantages of the present invention are apparentfrom the written description above and it is intended by the appendedclaims to cover all. Furthermore, since numerous modifications andchanges will readily occur to those skilled in the art, it is notdesired to limit the invention to the exact construction and operationas illustrated and described. Hence, all suitable modifications andequivalents may be resorted to as falling within the scope of theinvention.

1. A manufacturing method of a contact structure having a compliant bumpand a testing area, comprising: 1) preparing a substrate having at leastthe contact structure; 2) coating a polymeric material upon the contactstructure; 3) developing/etching the polymeric material so as to formone or more than one of the plurality of compliant bumps and the testingarea on the contact structure; and 4) covering a conductive material,the compliant bump forms a conductive bump; whereby, the conductive bumpelectrically connects with the testing area by means of the conductivelayer, so the testing area conducts the conductive bump.
 2. Themanufacturing method of claim 1, wherein the substrate is an organic orinorganic material such as ceramic, metal, glass, polymeric or silicon.3. A manufacturing method of a contact structure having a compliant bumpand a testing area, comprising: 1) preparing a silicon wafer having ametal pad as an input/output terminal, and a passivation layer which isused to protect the body of the wafer; 2) coating a polymeric materialupon the silicon wafer; 3) developing/etching the polymeric material soas to form one or more than one of the plurality of compliant bumps andthe teqting area on the metal pad; and 4) covering a conductive materialon the testing area of the compliant bump which forms a conductive bump;whereby, the conductive bump electrically connects with the testing areaby means of the conductive layer, so the testing area conducts theconductive bump.